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Dalrymple (1991, p.
376f),
James Moore and many
others have argued that the absence of naturally occurring short-lived
radioisotopes on Earth indicates that our planet is billions of years old
rather than the 6,000 to 10,000 years as proclaimed by young-Earth
creationists (YECs). In particular, Dalrymple (1991, p. 376-377) notes that
there are 34 known radioisotopes with half-lives of greater than one million
years. Only five radioisotopes with half-lives between one million and 80
million years are known to naturally regenerate on Earth, the Moon and/or in
the space surrounding our planet. Specifically, nuclear physicists have
determined that cosmic rays may produce 53Mn (half-life of
3.7 million years), 10Be (half-life of 1.6 million years),
and 129I (half-life of 17 million years) (Dalrymple, 1991,
p. 376-377). 129I may also form in terrestrial uranium-rich
rocks from the spontaneous fission of 238U (Dalrymple, 1991,
p. 376-377; Moran, 1996, p. 686). Slow neutrons interacting with uranium ores
may generate236U (half-life of 23.9 million years)
(Dalrymple, 1991, p. 376-377). Although it is not known to naturally occur on
Earth, cosmic rays produce 237Np (half-life of 2.14 million
years) on the surface of the Moon (Dalrymple, 1991, p. 376-377). Otherwise,
NO naturally occurring radioactive isotopes with half-lives between one
million and 80 million years have been found in our Solar System (Dalrymple,
1991, p. 377). If the Earth is only 6,000 to 10,000 years old as YECs claim,
where are these relatively short-lived radioisotopes, namely: 146Sm,
205Pb, 247Cm, 182Hf, 107Pd, 135Cs, 97Tc, 150Gd, 93Zr, 98Tc, and 154Dy?

Dalrymple (1991, p.
376) proposes three SCIENTIFIC hypotheses to explain the absence of these
short-lived radioisotopes:

1. it's simply chance;

2. the stellar, supernovae
and other processes that synthesize elements failed to produce these
radioactive isotopes;

3. the Earth is
ancient and these radioisotopes decayed away long ago.

Dalrymple (1991, p.
378) calculated the probability that a 10,000 year old Earth would have, by
chance alone, all radioactive isotopes with half-lives greater than 80 million
years and NO non-regenerated radioactive isotopes with half-lives between
1,000 and 80 million years. The probability is a remote one chance in
300,000,000,000,000!

Elements may be easily
detected in stars by analyzing their radiation emission spectra. These
procedures actually discovered helium in the Sun before it was found on
Earth! While non-regenerated short-lived radioisotopes are absent from the
Earth, Sun and Moon, they have been found forming in stars that are much more
massive and/or violent than our Sun. For example, 97Tc,
which only has a half-life of 2.6 million years, has been detected in some
stars (Dalrymple, 1991, p. 380). Promethium (Pm) has also been found forming
in stars. The longest half-life of a Pm isotope is only 18 years (Dalrymple,
1991, p. 380). Furthermore, Dalrymple (1991, p. 379-384) discusses in some
detail the stellar nuclear reactions that can produce short-lived
radioisotopes and how the stable daughter products of extinct short-lived
radioisotopes have been found in meteorites and other samples. There is no
doubt that short-lived radioisotopes are capable of forming in supernovae and
dense stars and that at least some of them existed at one time in our Solar
System. However, they don't currently appear in natural materials in and
around the Earth. The only rational and scientific explanation is that the
Earth is billions of years old.

The two
terrestrial-occurring non-regenerating radioisotopes with the shortest
half-lives are 235U (half life of 704 million years) and 244Pu (half life of only 82 million years). Although natural
244Pu was found, its concentration was so low that it was
barely detected. Through extraordinary separation techniques, a total of 8 x
10-15 grams of 244Pu was extracted from 85
kilograms of molybdenum ore from a California mine (Dalrymple, 1991, p. 386).
This is hardly abundant and much rarer than what we would expect if the Earth
was only 6,000 to 10,000 years old. To be exact, Dalrymple (1991, p. 386)
calculates that if the Earth were only one billion years old, 244Pu
would be in high enough concentrations that it would be easily found.
Furthermore, missing radioisotopes, such as 146Sm, should be
easily detected if the Earth was one billion years old or younger (Dalrymple,
1991, p. 386).

The lack of
short-lived radioisotopes and the presence of radioisotopes with longer
half-lives are clearly consistent with a 4.6 billion year old Earth. They
also completely refute any creationist claims for a "young" Earth. To explain
away the absence of short-lived radioisotopes in terrestrial materials, some
YECs might hide behind the old flimsy excuse that "God just made the Earth
that way" or that for some reason "God arbitrarily sped up radioactive decay
rates during the Creation, Fall and/or Flood, but not during the
Crucifixion." In other words, they would just invoke ad hoc and
irrational
miracles and leave it at that. To his credit, YEC Woodmorappe (1999, p.
26) avoids invoking this anti-scientific "escape hatch". Although Woodmorappe
(1999) includes citations of Dalrymple (1991), he (1999, p. 26) blatantly
ignores Dalrymple's (1991, p. 376-387) discussions of radioisotopes and how
they undermine young-Earth creationism. Instead of recognizing that both
natural and artificial (e.g., Hou et al., 2003) processes may
produce 129I, Woodmorappe (1999, p. 26) wants to believe
that the well-understood nuclear physics of regenerated radioisotopes is only
an "assumption". He also selectively cites Moran (1996) and suggests that the
presence of 129I in 12 brines (very salty groundwaters) from
the Anadarko Basin of Oklahoma, USA, is due to their "young" age rather than
fissiogenic regeneration from 238U. Yet, Woodmorappe (1999)
fails to mention the following statement by Moran (1996, p. 688), which
supports a fissiogenic origin for 129I and undermines his
YEC agenda:

The range in 129I/I
ratios [for the Anadarko Basin brines] is 95 to 348 x 10-15, with
no obvious correlation with depth or with I concentration. These ratios are
among the lowest measured to date on natural materials, CONSISTENT with the
assumption that these waters have been hydrologically isolated from the
atmosphere FOR MORE THAN 100 m.y. [my emphasis]

By looking at the
hydraulic properties and organic geochemistry of the subsurface rocks in the
basin, Moran (1996, p. 685, 690-692) concluded that the relatively organic-
and uranium-rich Woodford Shale was the probable source of the radioactive
iodine.

YECs have yet to
produce any evidence of non-regenerated, short-lived isotopes in the geologic
record. Where are they if the Earth is only 6,000 to 10,000 years old? Why
haven't they been found in some of the countless routine mass spectrometry and
other analyses of rocks, sediments, soils and water that are run each day?
With all of these detailed analyses, where are they? Again, the search for
natural plutonium has been
intense, yet only tiny amounts have been found. Why should this search be
so difficult if the Earth is young? Clearly, Woodmorappe and other YECs need
to find short-lived radioisotopes that cannot be attributed to natural
regeneration, such as: 146Sm, 205Pb, 247Cm, 182Hf, 107Pd, 135Cs, 97Tc, 150Gd, 93Zr, 98Tc, or 154Dy.
Until they do, there's no reason to take their farfetched religious claims
seriously.

REFERENCES

Dalrymple, G.B., 1991, The Age of the Earth,
Stanford University Press, Stanford, California.